用光腔衰荡技术测量镜片的反射率

Analysis of reflectivity measurement by cavity ring-down spectroscopy

摘要: 根据光腔衰荡光谱技术原理，建立了测量镜片反射率的实验装置。利用该装置测定了一对反射率相等的高反射腔镜，反射率测试结果为（99.925±0.001）%;以22.5°将直腔变为折叠腔，测得的反射率为（99.992±0.003）％。重复测定反射镜样品的反射率，精度达到10－5。该测量装置可用于超低损耗薄膜高反射镜反射率的精确测量。轻微移动探测器位置，对腔镜的测试结果影响不大。

Abstract: This paper presents the experimental method to measure the high reflectivity of optical mirror by cavity ring-down spectroscopy. The experimental system uses a straight cavity composed of a pair of cavity mirrors with same reflectivity or a folded cavity which is formed from the straight cavity to be folded at 22.5° angle, a reflector is laid at folded point.The reflectivity of the cavity mirrors is measured to be（99.925±0.001）% and the reflector to be (99.992±0.003)％．The metrical precision achieves 10－5.The low loss and high reflectivity mirrors can be measured accurately by this setup．